How is someone identified as having stage 2 type 1 diabetes?

Stage 2 type 1 diabetes is a pre-symptomatic state: two or more islet autoantibodies are present in the blood, and blood glucose testing shows early abnormalities — but there are no symptoms of diabetes at all. It is detected through screening of first-degree relatives (children, parents, siblings) of people who have type 1 diabetes. Without active autoantibody screening, stage 2 T1D is not detectable in routine clinical assessment. Type 1 Diabetes TrialNet offers free screening to first-degree relatives in Australia.

Will teplizumab be available on the PBS?

Not yet. TGA registration (which happened in June 2026) means the drug has cleared the safety and efficacy bar. PBS listing is a separate process, assessed by the Pharmaceutical Benefits Advisory Committee (PBAC). Until a PBS listing is granted, teplizumab's cost remains the patient's or private insurer's responsibility. In the United States, the list price for a single 14-day course is approximately USD 193,000. Most Australian families would not be able to access this without a PBS subsidy.

Teplizumab approved: Australia can now delay type 1 diabetes onset

What just happened

The Therapeutic Goods Administration registered teplizumab (Tzield) on 4 June 2026 — making Australia one of the first countries after the United States to approve the first genuinely new therapeutic approach to type 1 diabetes in more than a century.

Teplizumab does not treat type 1 diabetes. It delays it. Specifically, it delays the transition from stage 2 to stage 3 disease — from the invisible autoimmune phase into the clinical presentation that requires insulin to survive. RACGP newsGP described the approval as the first time medicine has had something to offer the people living in that in-between space: autoantibodies active, glucose shifting, and no way to know when the threshold would be crossed.

The pivotal data comes from the TN-10 trial, which enrolled 76 people aged 8 to 45 who were identified through screening as having stage 2 T1D — two or more islet autoantibodies in their blood plus early glucose abnormalities, but no symptoms. A single 14-day intravenous course of teplizumab delayed the onset of clinical diabetes by a median of 24 months compared to placebo. At the end of the trial, 57% of participants in the teplizumab group remained diabetes-free, compared with 28% in the placebo group. Longer follow-up data has since suggested the benefit may extend to seven or more years in some individuals.

For the woman who has watched a child or sibling diagnosed with type 1 diabetes, who has been carrying a glucagon kit and reading everything she can find about genetic risk — this approval is not a cure. But it is the first time medicine has had something to offer before the diagnosis lands.

The both-and

This is a real therapeutic advance in a field that has not had one in over 100 years. It is also not a silver bullet, and the access question is unresolved.

What stage 2 type 1 diabetes actually means

Type 1 diabetes has three recognisable stages. Stage 1 is the earliest: islet autoantibodies present but glucose completely normal. Stage 2 adds glucose dysregulation — the pancreatic beta cells are under active immune attack and blood sugars are starting to shift abnormally, but the person has no thirst, no weight loss, no ketones — no symptoms at all. Stage 3 is the disease most people recognise: symptomatic, requiring insulin to stay alive.

Stage 2 is essentially invisible in routine clinical settings. It is detected by measuring islet autoantibodies — including anti-GAD65, anti-IA-2, and anti-ZnT8 — and running oral glucose tolerance tests in people with a first-degree relative with type 1 diabetes. Type 1 Diabetes TrialNet offers free screening to first-degree relatives of people with T1D in Australia. Without this kind of active screening programme, stage 2 disease is not detectable in routine general practice at all.

The mechanism

Teplizumab is a humanised anti-CD3 monoclonal antibody. CD3 is a surface marker on the T-cells responsible for the autoimmune attack on pancreatic beta cells in type 1 diabetes. The drug modulates the T-cell response, dampening — not eliminating — the autoimmune attack. The result is a slowing of beta cell destruction that buys time before the pancreas drops below the threshold needed to maintain normal glucose without insulin.

The 14-day intravenous infusion course is administered in a hospital or infusion centre setting and requires close monitoring during the infusion period. It is not a self-administered therapy, and a specialist referral pathway — typically to paediatric or adult endocrinology — is needed.

The access problem is real

As one of Australia’s leading endocrinologists told AusDoc, TGA registration and PBS listing are two entirely separate thresholds. Clearance through the TGA means the drug has passed the safety and efficacy bar. It does not mean the government has agreed to subsidise it. In the United States, the list price for a single 14-day course of Tzield is approximately USD 193,000. Australian pricing has not been announced, but the scale of cost is not likely to differ meaningfully without a subsidy pathway.

A PBAC application is the next step that matters for most patients. Without it, this approval benefits those who can access private specialist services and meet the costs themselves — a reality that sits uncomfortably against a disease that disproportionately presents in childhood. Diabetes Australia has called for expedited PBAC review and is maintaining up-to-date information for families navigating this new landscape.

2 cents

If a first-degree relative has type 1 diabetes — a child, sibling, or parent — this week’s approval makes a conversation with your GP or an endocrinologist about autoantibody screening worth raising. The TrialNet programme offers free screening to first-degree relatives, and it is the only current pathway to detecting stage 2 disease before symptoms appear.

The GP’s practical role right now is to be informed enough to answer the question when it arrives in the consultation. Yes, there is now a TGA-approved therapy that can delay progression in those with stage 2 T1D. Yes, it requires specialist referral and intravenous infusion. No, it is not yet accessible through the PBS, which means most families are waiting on the PBAC process. Being oriented to this before the patient asks is the more useful starting position.

This is general health information and does not constitute individual clinical advice.

Verdict

Verdict: yes — worth knowing about.

The TGA approval of teplizumab marks the first genuinely new therapeutic option in type 1 diabetes in over a century. For anyone with a first-degree relative with T1D, autoantibody screening conversations in general practice are now clinically relevant in a way they were not before. The PBAC pathway — and what it means for access — is the next critical watch point.